System Development Phase / 7 Stages of SDLC
- It is a methodology used to develop, maintain and replace information system.
- Also known as system/software development life cycle(SDLC)]
- SDLC mainly consist 7 phase which have a chronological order ie it following the order in which they occurred.
- System study/ Preliminary Investigation and Feasibility study
- System analysis or determination of system requirements
- System design
- System development
- System testing
- System implementation
- System maintenance and reviews/ Evaluation
For remembering , make a formula(SAD D TIM –> sad the team => study analysis design development test implement maintenance)
Fig: 7 Stages of System Development Life Cycle
1. System Study
- First step of SDLC
- Also known as preliminary investigation or need analysis
- System study mainly focus
- Study the organizational structure and problems and collect data from various source
- Analyzing the current system and develop different possible solution
- Selecting the best solution and feasibility study.
- System analysis starts with identify the problems or the organization, creates different solutions, choose best solution and finally make a preliminary draft for feasibility study.
- Feasibility is the determination (calculation) of whether or not a system or project is worth doing. The process followed in making this determination is called a feasibility study.
- So it tells us whether the system is feasible to design nor not.
- It is the test of the proposed system in its workability, meeting user’s requirements, effective uses of resources and cost effectiveness.
Types of Feasibility Study
System analyst usually conducts different seven types of feasibility study.
- Technical Feasibility:
- Technical feasibility is concerned with the availability of hardware and software required for the development of the system.
- Determines the adaptation of new technology
- Determines the availability of the required technical manpower to develop the system
- Economical Feasibility:
It is the measure of cost effectiveness of the project. The economic feasibility is nothing but judging whether the possible benefit of solving the problems is worthwhile or not. It includes:
- It concerns with the return of investment in the system.
- It determines whether the system is affordable or not.
- It identifies the financial benefits and cost benefit analysis associated with system.
- It determines whether the system’s goals cab be achieved within the budget.
- Operational Feasibility:
It studies whether the human resource available in the organization is capable to operate the system or not.
- It determines the general skills, training and capabilities of the existing personnel.
- Determine whether—and how well—the organization’s needs can be met by completing the project.
- It mainly related to human organizational and political aspects.
- Social Feasibility:
- Social feasibility is a determination of whether a proposed system will be acceptable to the society or not.
- Social feasibility determines the impact of the system to the employees. Job replacement is also a key factor to the analysis.
- Social feasibility covers more than just human issues, it includes the environmental aspects, traditions, values and ethics.
- Management Feasibility:
It is a determination of whether a proposed system will be acceptable to management team or not.
- Legal and contractual Feasibility:
Legal feasibility determines whether a proposed system infringes (violate) on known acts, statues as well as legalization. It concerns with the legal effects like taxation, copyright, patent, trademark, labor laws as well as effects of hardware, software license agreement.
- Time Feasibility:
It mainly concern with the project deadlines and time frame for system completion.
Need of Feasibility Study
- It determines whether the system meets the goal of the clients or not
- Determines the strengths and limitations before starting to develop the system.
- It helps to increase investment in the system
- It focuses on the boundary of the system goal.
- It suggests new opportunities through the investigation process.
- It helps in obtaining fund from financial institutions and other sources.
- It provides quality information for decision making.
- It helps to increase investment in the system.
2. System Analysis – comming soon
3. System Design – comming soon
4. System Development or Development of Software
- After designing a logical diagram of a system then next step is to convert into program. This process is called system development.
- Developers/Programmers play a key role in system development, creating or customizing the system.
- Flowchart, algorithm, Pseudo code, etc. studies and convert it into usable output as a system.
- The major goal of this phase is to translate the problem studied in the system analysis and design phase into proper physical system.
- Programmers are also responsible for the documentation and provide explanation of workflow for the testing purpose.
5. System Testing
- System testing is a level of software testing where complete and integrated software is tested.
- The purpose of this test is to evaluate the system’s compliance with the specified requirements.
- Software testing is the process of evaluation a software item to detect differences between given input and expected output.
- Testing assesses (evaluate) the quality of the product.
- There are many types of testing like
a. Unit Testing:
- Unit testing is the testing of an individual unit or group of related units after the component is developed.
- This task is performed before the integration of individual units to create a whole system.
- It is often done by the programmer to test that the unit he/she has implemented is producing expected output against given input.
- While testing individual units, undesirable happening must be noted and debugged (correction) instantly before jumping to next unit or integrating with another unit.
- This task is done by developer/programmer.
- Integration testing is testing in which a group of components are combined to produce output.
- First, all the individual units combine together which was tested before in previous phase and again tested after combination.
- Also, the interaction between software and hardware is tested in integration testing if software and hardware components have any relation.
- This test is also done by developer/programmer.
- This process is important as it helps to identify and remove any errors after combination as well as error hides during unit testing.
- This is the process of testing the complete system after integrating all units.
- After testing the units and integrated system, all units are combined and create a complete system.
- Input and output of the complete system is analyzed.
- If the system not working as designed during this testing, further process of error detection, correction, implementation and testing process will be run until it meets its desire output.
- Normally white box and black box testing is performed in this phase.
- Black box testing is the testing of internal functionality testing of program which is hidden from general user.
- White box testing is the testing of outer structural of the system and even regular user can feel it.
d.User Acceptance Testing:
Acceptance testing is often done by the customer to ensure that the delivered product meets the requirements and works as the customer expected.
6. System Implementation
- This is the process of installing developed system to the clients working environment.
- In general, it is the process of converting theory to practical.
- It involves the testing, debugging and loading (set up) the developed system to the user sites and training the user personnel.
- This phase consists of implementation of the system into a production environment, and resolution of the problem identified in testing phase.
- The process of moving from old system to new one is called system conversion. There are different ways of system conversion.
- Direct Conversion: all users must stop the old system and new system is implemented. It takes time to run smoothly since, training and support goes simultaneously.
- Parallel Conversion: All users use both old and new system simultaneously. All the outputs are compared and switch to new system if they satisfied.
- Phased Conversion: All users switch to new system phase by phase. After completing one phase another phase is implemented.
- Pilot Conversion: In this conversion, small components is used by small unit of the organization, test and this component is install. Another unit is test by another group of users and so on. Finally all the components will be implementing, testing unit by unit.
7. System Maintenance and Review
- Correcting and upgrading process of the system is called system maintenance.
- It begins after the system is implemented.
- Like any system, there is an ageing process that requires periodic maintenance of hardware and software.
- The content of the review will include objectives met, cost, performance, standards and recommendation.
- It has been seen that there are always some errors found in the system that must be noted and corrected.
- The maintenance can be classified as
- Corrective maintenance – correction of the system errors occurred due to ill-defined problems.
- Adaptive maintenance- changing the program/ functions to meet system requirement
- Perfective maintenance – change the program/function to enhance the performance of the system.
It is the last step of the system development process, where all units of design, analysis, development, testing and implementing individuals as well as client representatives set together to see if the system has meet the objectives of the System or not.